It works everywhere else, but not on AIX

[John R. Miller]

In article <1991Apr15.182214.10391 at ux1.cso.uiuc.edu> phil at ux1.cso.uiuc.edu (Phil Howard KA9WGN) writes:
>First of all, the "df" command does not always know how to find the file
>system a particular path name it is given is on.  This is what I get:
>
>	phil at ux2:/u/phil 2> df .
>	Filesystem    Total KB    free %used   iused %iused Mounted on
>	Cannot find file system .
>	phil at ux2:/u/phil 3> pwd
>	/u/phil
>
>So apparently I need some other way to find out the file system I am on
>that is also portable over other UNIX platforms.  Until AIX, that was "df"
>itself.
>
>If IBM "designed" it this way... WHY?

I can't tell from your posting which version of AIX you're running.

This is normal USG behavior.  On SysIII machines (for example) one has
to give df a mount point or special file (i.e., a file system).  This is
the way df behaves on AIX2.2.1 on the rt.

BSD allows one to specify a file and returns the free space of the file
system on which it resides.  "." is a common choice, but any file will
do.  This is the way df behaves on AIX3.1 on the s/6000.  There was a
problem with early releases of 3.1 in that df was suid bin so that if
"." (or whatever) wasn't readable by bin df would fail.  This has been
corrected in later releases (3.1.5, I think.)  Of course, it's simple
enough to correct: just un-suid df.
-- 
John R. Miller   13102 Briar Hollow Dr.   Austin, Texas  78729
hm: 512/331-0155 john at crcaus.cactus.org  or ..cs.utexas.edu!bigtex!crcaus!john
wk: 512/823-3867 john at glasnost.austin.ibm.com